Heat exchange in catalytic reactions



p 1941- E. J. HOUDRY 2,255,058

HEAT EXCHANGE IN CATALYTIC REACTIONS Filed D60. 7, 1937 INVENTOR EugeweJHmudrH BY I ATTO R N EY Patented Sept. 9, 1941 UNITED STATES PATENT OFFICE HEAT EXCHANGE IN CATALYTIC REACTIONS Eugene J. Houdry, Haverford, Pa., assignor to Houdry Process Corporation, Wilmington, Del., a corporation of Delaware Application December 7, 1937, Serial No. 178,514

Claims.

ous operation. Other objects will be apparent from the detailed description which follows.

The invention involves the temperature control of reactions by the character and the extent of movement of heat exchange fluid within and through the reaction zone and the utilization of gravity to produce a part of such movement. The direction of movement of the heat exchange fluid in a given reaction zone may differ with the type or with the intensity of the reaction. The heat exchange means for a battery of two or more converters are connected into a single circuit and provision is made for circulation under pressure and against gravity at any desired rate through a part of the circuit which may include the converters in which the reaction is intense and for circulation by gravity through the remainder of the circuit which preferably includes the converters having milder reactions. The temperature of the heat exchange medium is regulated at one or more points in the circuit and preferably by its temperature at another point in the circuit.

Concrete illustrations of the invention are indicated in the accompanying drawing, in which:

Fig. 1 is a diagrammatic showing of a battery of converters and of a circuit for a heat exchange medium:

Fig. 2 is a fragmentary vertical sectional view through one form of converter, the section being substantially on the line 2-4 of Fig. 1; and

Fig. 3 is a vertical sectional view similar to Fig. 2, but showing another'type of converter adapted for use in the circuit shown in Fig. 1.

In Fig. 1, three converters 4 are indicated as making up a battery adapted for simultaneously effecting chemicalreactions; it isto be understood, however, that any desired number of con- Another object is to devise heat exchange circuits and their operation for converters, es-' pecially when arranged in a battery for continuexchange medium is sent at proper temperature through the reaction chambers of all of the converters, so as to control the reactions taking place therein. Any suitable heat exchange fluid may be employed but by preference the medium is a,

liquidwhich does not change state, such as molten metals and metallic alloys, fused salts, etc.

The circuit for the heat exchange medium is so arranged that the medium may pass into and.

out of heat exchange members in the respective reaction chambers in either direction and either against gravity or by gravity. For the against gravity movement of liquid, a header 5 is provided with valves branches 6 leading to each conx verter, the liquid then being arranged to leave each converter through valved branches I which join header 8, the latter discharging into a surge tank 9 of any desired type. Gravity flow from surge tank 9 is provided by a suitable connection 10 to header H, which has valved branches H to each of converters 4, such gravity flow leaving the converters by valved connections I3 to a header I I, which connects, by line IS, with temperature modifying means such as a heat exchanger l6 of any known or desired type. After temperature modification in heat exchanger IS, the heat exchange medium leaves by line [1, which contains suitable impelling means such as pump l8 for forcing the liquid back into header 5. An overflow connection l9 from surge tank 9 to heat exchanger I6 insures adequate return of the liquid to supply the requirements of pump l8.

The valves in the various connections from converters 4 to the various headers are so arranged and set that the heat exchange liquid is in motion throughout the entire circuit which includes the heat. exchange conduits extending into the reaction chambers of converters 4. Such motion is, in part, induced by the impelling means, such as pump l8, and, in part, by gravity flow from surge tank 9. The liquidat each of these sources of flow must be at the proper temperature to control the chemical reaction taking place in the converter or converters to which the liquid is then directed. Accordingly, heat exchanger I6 is provided adjacent to pump 18, and a similar heat exchanger (not shown) may be provided, if required or desired, in line 8 leading to surge tank 9, or in line In leaving the same. Automatic regulation of the temperature of the heat exchange medium in one part of the circuit may be regulated by its temperature in another part of the circuit. For example, the circuit may be set up to deliver the heat exchange medium verters may be in the battery. The same heat into the surge tank 9 at a given temperature,

22 for a valve or pump 23 in supply line 24 to heat exchanger I 6.

- The chemical converters may be of any known or suitable type, and the heat exchange units or elements extending into the reaction chambers thereof may also be of any known or suitable type, such as single conduits, nested conduits, or

radiator elements. By way of illustration Fig. 2

shows a horizontal type of converter 4a, having one or a series of reaction chambers 24 filled with suitable contact or catalytic material M. A grid or perforated partition 25 separates the reaction chamber from a manifolding chamber 26 for reaction products defined by end wall. 21.. The heat exchange elements E as shown are in horizontal parallel relationship and are of the nested conduit type, comprising. inner conduit e and outer conduit e in concentric arrangement. Elements E, as indicated, extend entirely across manifolding chamber 26, outer conduits e being secured in end wall 21 to communicate with manifolding chamber 28 for the heat exchange medium, which is separated, by a partition 29, froman outer manifolding chamber 30, also for the heat exchange medium. Inner conduits e of the heat exchange elements extend across manifolding chamber 28, and are secured in partition 29 to communicate with manifolding chamber 30.

Fig. 3 shows another type of oonverterwhich I may be utilized to makeup the battery. Converter 4b is of the vertical type having a perforated partition 25b adjacent its lower end to separate reaction chamber 241), containing mass M, from the manifolding chamber 26b for reactants or reaction products. There is a similar manifolding chamber 3| at the opposite end of the converter. The same type of nested heat exchange element E is shown in Fig. 3 as in Fig. 2, but, in this instance, the elements are disposed in vertical parallel arrangement. Another minor difl'erence is that the elements E in Fig. 3 have nested manifolds, rather than' large adjacent manifold chambers, for supplying and venting the heat exchange fluid. These nested manifolds comprise an outer manifold conduit 32, which connects with the outer conduits e of each of elements E, and an inner manifold 33. which connects with each of the inner conduits e of elements E.

It will be clear, from an inspection of Figs. 2 and 3, that, when the converters shown therein are receiving pressure flow of the heat exchange medium against gravity, the medium will pass (from line 5 by'valved connection 8) into manifolding chamber 30 of Fig. 2, or into the inner manifolding pipes 33 of Fig. 3, thence into the inner pipes e of elements E, which discharge into outer conduits e at the remote ends thereof, passing back in reverse flow through the latter, to discharge into manifolding chamber 28 in Fig. 2, or into manifolding pipes 32 of Fig. 3, whence they pass, by branch I and header connection 8, into the surge tank 3 of Fig. 1. If, on the other hand, the converters in Figs. 2

and 3.are receiving the heat exchange medium remote ends thereof, where the medium enters inner pipes e of elements E and discharges into manifolding chamber 30 of Fig. 2 or into manifolding pipe 33 of Fig. 3, whence it passes, by valved connection I 3, into header I 4, which conducts the medium, by connection 15 (Fig. 1), to heat exchanger Hi, to again pass, by line if, into the pressure circulated part of the system.

The invention is susceptible of wide use in the chemical industry'when reactions of different intensities take place at the same or at somewhat diiferent temperatures. By way of example, one use to which the invention is particularly adapted is in the conversion or transformation of high boiling hydrocarbons into lower boiling hydrocarbons for the production of motor fuel or gasoline. Such a conversion is advantageously effected as a mild endothermic reaction by the use of silicious catalysts operating usually in the temperature range of 800 to 900 F. and capable of being regenerated by oxidation in a strongly exothermic reaction, which is usually controlled so as not to exceed a temperature of about 1050 F. The reactions take place in alternation, with the on-stream or transforming period being usually of the same length or half the length of the regeneration period. If the periods are of the same length, two converters -will be utilized or multiples of two; while, if the regenerating period is twice the length of the on-stream period, the converters will be in multiples of three, with two converters in regeneration while one is on stream. This latter arrangement is illustrated in Fig. 1. Assuming, then, by way of a specific example that the masses M in the three converters are of proper silicious composition, and that the transforming reaction is to take place at a temperature of about 835 or 840 F., the heat exchange circuit is arranged to force the heat exchange medium, such as fused salts, by pump l8, into header 5 and through the heat exchange elements E of two of the converters such as shown in either Fig. 2 or Fig. 3, so as to be delivered by header 8 into surge tank 9 at a temperature of about 860 F., and thus to provide the required heat for the endothermic transforming operation in the single. converter 4 which receives the heat exchange medium by gravity flow from surge tank 9. To have a temperature of 860 F. in the surge tank 9, pump [8 will force the heat. exchange medium into the converters in regeneration at a considerably lower temperature, as at about 800 F. The heat exchange medium will leave the converter on stream in the gravity flow side of the circuit at a temperature of about 830 F., so that only some 30 need be removed from the heat exchange medium in the temperature modifying apparatus or heat exchanger l6, flow of the temperature modifying ent through the heat exchanger being preferably automatically controlled by the thermostat 20 and associated control apparatus 2|, 22, and 23. The valves in the various connections may be of any desired type, simple flap valves being often available for use, since slight leakage willnot usually upset the operation.

The valves may be hand operated or automatiby the length 01' the cycle, the number 01' conexchange members E which include the mounting of the manifolds or manifold chambers at one end of the converter and a better equalization of temperature especially when long heat exchange members E are needed.

From the above, it will be apparent that the present invention effects a simplification of the size and extent of apparatus needed for effective temperature control of a series of chemical reactions by utilizing gravity for a portion of the flow of the heat exchange medium, especially tor the control of reactions which are relatively mild; that pressure circulation at any desired rate is also provided for reactions which involve large or extreme temperature changes; and that the combination of pressure flow and gravity flow permits ease of adjustment of the temperature of. the heat exchange medium in parts or the circuit, so as economically to regulate, in an efficient manner, difierent types of reactions by one and the same heat exchange circuit.

I claim as my invention:

1'. In the control 01 chemical reactions effected in the presence 01 a body or contact material having concentric reverse flow channels therein for a heat exchange medium and wherein the contact material is used to carry out alternating reactions which have diflereht heats oi reaction, the process of controlling the temperature of the contact material which comprises sending the heat exchange medium first into the inner or the concentric channels for controlling the temperature of the contact material when subjected to the greater heat or reaction and first into the outer or the concentric channels for controllin the temperature or the contact material when subjected to the lesser heat 01 reaction.

2. In the temperature control or a contact mass utilized for the promotion in alternation or strong exothermic and mild endothermic reactions, the mass having a plurality oi concentric reverse flow channels therein tor a heat exchange medium, the process step of forcing the heat exchange medium at suitable temperature and rate into the inner or said concentric channels during the strong exothermic reactions and returning the heat exchange medium at higher temperature in gravity flow into the outer or said concentric channels during the mild endothermic reactions.

3. In the control or chemical reactions effected simultaneously in a plurality or chambers containing contact material and involving an endothermic catalytic reaction in certain of said chambers while catalyst simultaneously is undergoing exothermic regeneration in certain other or said chambers and wherein it is necessary to extract a greater amount or heat from a chamber undergoing regeneration than it is necessary to add heat to a chamber undergoing endothermic reaction. the process or controlling the temperature or the chambers which comprises connecting the reaction chambers with a circulating system comprising a return side including pumping means and a gravity side ineluding a reservoir tor receiving liquid trom the pumping side, continuously circulating the liquid in heat exchange relation with the contact material in the chambers by pumping a volume or the liquid from the return side at the desired rate in indirect heat exchange relation with the contact material which is undergoing regeneration to the reservoir in the gravity side, sending a lesser volume of the liquid from the reservoir in the gravity side at a lower rate in indirect heat exchange relation with the contact material which is subjected to the endothermic reaction to the return side of the system, and returning directly from the reservoir to the return side excess liquid for supplying that side of the system.

4. In the control of chemical reactions effected simultaneously in a plurality of chambers containing contact material and involving an endothermic catalytic reaction in certain 'of said chambers while catalyst simultaneously is undergoing exothermic regeneration in certain of said chambers and wherein it is necessary to extract a greater amount of heat from a chamber undergoing regeneration than it is necessary to add to a chamber undergoing endothermic reaction, the process or controlling the temperature or the chambers which comprises connecting the reaction chambers with a circulating system comprising a return side including pumping means and a gravity side including a reservoir for receivlng hquid from the pumping side, circulating the hqlud in heat exchange relation with the contact material in the chambers by pumping a volume or the liquid from the return side at the desired rate in indirect heat exchange relation with the contact material which is undergoing regeneration to the reservoir in the gravity side, sending a lesser volume of the liquld rrom the reservoir in the gravity side at a lower rate in indirect heat exchange relation with the contact material which is subjected to the endothermic reaction to the return side or the system, returning directly from the reservoir to the return side excess liquid for supplying that side 01 the system, and adjusting the temperature oi the heat exchange liquid before again pumping it from the return side of the system.

5. In the control of chemical reactions effected simultaneously in a group of chambers containing contact material wherein certain of the group are subjected to an intense reaction and the others are subjected to a mild reaction, the process or temperature regulation which comprises connecting the chambers with a circulating system for heat exchange liquid comprising a return side including pumping means and a grav-' ity side including a reservoir above the chambers, continuously circulating the liquid in indirect heat exchange relation with the contact material in the chambers by pumping it from the return side at the desired rate upwardly through said certain chambers which are subjected to the intense reaction to the reservoir in the gra ity side, passing a desired portion of the liquid from the reservoir at a lower rate downwardly through the other chambers to the return side or the system, returning directly from the reservoir to the return side excess liquid for supplying the system and adjusting the temperature of the liquid before recirculation by controlling its temperature in response to the temperature of liquid in the reservoir.

EUGENE J. HOUDRY Patent No. 2,255,058.

cERTIFicATE OF CORRECTION. I

I September 9, 19in. f EUGENE J. HOUDRY.

It is here b3 certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, sec-- 0nd column, line 114, for the word "valves" read "valved"; page 2, first column, line 22, after "for" insert --reactan ts or--; and that the said Letters Patent .should be read with this 'correction therein that the same may conform to the record of the case in the Patent Office. Signed and sealed this lhth day of October, A. D. 19m.

Henry Van Arsdale,

(Seal) Acting Commissioner of Patents. 

